1. Technical Field
The present invention relates to an element structure, an inertia sensor, and an electronic device.
2. Related Art
Recently, there has been interest in a technology capable of implementing a small-sized and highly sensitive micro-electro mechanical system (MEMS) sensor using a MEMS technology.
For example, JP-A-2004-286535 discloses a semiconductor dynamic quantity sensor using a stacked structure of polysilicon. The semiconductor dynamic quantity sensor uses a single movable structure to detect an acceleration component in the direction of each of three axes (X axis, Y axis, and Z axis).
Further, JP-A-9-113534 discloses a triaxial acceleration sensor in which three acceleration detection elements are integrated on a single silicon substrate. The three acceleration detection elements are simultaneously formed by a process of manufacturing a silicon micro machine. Further, each acceleration sensor is disposed on the single silicon substrate to be adjacent (juxtaposed) to each other.
In the technology disclosed in JP-A-2004-286535, it is necessary to provide three insulating separating structures in a direction perpendicular to a substrate within a structure. As a result, the manufacturing process becomes complicated. Further, since the acceleration in a triaxial direction is detected by a single movable structure, it is difficult to secure independence of detection sensitivity for each axis. In other words, it is undeniable that JP-A-2004-286535 has so-called other axis sensitivity characteristics. Further, there are limitations on improving the sensitivity of the sensor or reducing the sensor size due to the complexity of the structure. That is, since the electrode (polysilicon) is formed by a deposition process and it is difficult to thicken the layer in terms of the process, there are limitations on the improvement of sensor performance. Further, when performing sealing (packaging) of the sensor element, an additional process is required and the manufacturing process becomes more complicated. Further, the sensor size is further increased by forming the sealing body.
Further, in the technology of JP-A-9-113534, since three acceleration sensors are juxtaposed on a single sensor, an increase in the occupied area of the sensor is undeniable. Further, when performing sealing (packaging) of the sensor element, an additional process is required. Further, the sensor size is further increased by forming the sealing body.